A practical chemical synthesis of L-camitine （1） has been accomplished from （R）-3-chloro-1,2-propanediol （（R）-4）, which is a main by-product originated from （R,R）-Salen Co（III） catalyzed hydrolytic kinetic...A practical chemical synthesis of L-camitine （1） has been accomplished from （R）-3-chloro-1,2-propanediol （（R）-4）, which is a main by-product originated from （R,R）-Salen Co（III） catalyzed hydrolytic kinetic resolution （HKR） of （±）-epichlorohydrin. （R）-4 was utilized as a chiral starting material to prepare the key intermediate cyclic sulfite （（R）-S）. The new synthetic approach demonstrated an efficient utilization of organic by-product for the asymmetric synthesis of bioactive compounds.展开更多
目的：建立婴幼儿配方奶粉中3-氯丙醇酯的气相色谱—质谱联用（GC-MS）测定方法,并对部分市售婴幼儿配方奶粉中3-氯丙醇酯的含量进行调查。方法：用乙醚＋石油醚（1∶1）提取奶粉样品中脂肪,以1 m L甲醇钠甲醇溶液（0.25 mol/L）将脂肪...目的：建立婴幼儿配方奶粉中3-氯丙醇酯的气相色谱—质谱联用（GC-MS）测定方法,并对部分市售婴幼儿配方奶粉中3-氯丙醇酯的含量进行调查。方法：用乙醚＋石油醚（1∶1）提取奶粉样品中脂肪,以1 m L甲醇钠甲醇溶液（0.25 mol/L）将脂肪中的3-氯丙醇酯（3-MCPD酯）水解成3-氯丙醇（3-MCPD）并用硅藻土小柱净化后,经七氟丁酰基咪唑衍生,再用选择离子监测的气相色谱—质谱联用法测定,采用内标法定量。结果：3-MCPD酯在250~5 000μg/kg范围内线性良好（r〉0.999）,3个浓度水平下加标回收率为71.5%~99.6%,相对标准偏差为2.3%~6.0%。20份奶粉样品中,检出率65%,含量为0.26~0.97 mg/kg脂肪、0.042~0.22 mg/kg样品。不同阶段统计婴幼儿配方奶粉平均暴露量,一阶段3.32μg/（kg·bw）、二阶段2.42μg/（kg·bw）、三阶段2.72μg/（kg·bw）、四阶段0.23μg/（kg·bw）。结论：该方法灵敏度高、定量准确度,适合婴幼儿配方奶粉中3-氯丙醇酯的检测。展开更多
A novel oridonin derivative substituted with 3-((2,3-dihydroxypropyl)dithio)-propionyl group at 14-O position was synthesized through a two-step procedure:Esterification of oridonin with 3-(2-pyridyldithio)propanoic a...A novel oridonin derivative substituted with 3-((2,3-dihydroxypropyl)dithio)-propionyl group at 14-O position was synthesized through a two-step procedure:Esterification of oridonin with 3-(2-pyridyldithio)propanoic acid and the subsequent thiol-disulfide exchange reaction with 3-mercapto-1,2-propanediol.The bioreduction-responsive di-sulfide bond in the compound leads to high leaving ability of the 14-O acyl moiety when treated with glutathione as monitored by reverse phase high-performance liquid chromatography.展开更多
A novel NADPH-dependent carbonyl reductase was separated from Candida parapsilosis CCTCC 203011.The enzyme gave a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE),which was purified t...A novel NADPH-dependent carbonyl reductase was separated from Candida parapsilosis CCTCC 203011.The enzyme gave a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE),which was purified through ammonium sulfate,Diethylamino Ethanol(DEAE)sepharose Fast flow(FF),phenyl-sepharose FF and blue sepharose FF chromato graphy from cell-free extract.The molecular mass of the enzyme was about 30 kDa.The optimum pH and temperature for reduction were 4.5℃ and 35℃,respectively.The Cu2+had strong restrictive effect on enzyme activity.In addition,the carbonyl reductase was an enzyme with high substrate specificity and stereo-selectivity,and showed high asymmetric reduction activity towards a-hydroxyacetophenone and ethyl 4-chloro acetoacetate.For the asymmetric reduction of a-hydroxyacetophenone and ethyl 4-chloro acetoacetate,(S)-1-phenyl-1,2-ethanediol and(R)-ethyl 4-chloro-3-hydroxybutanoate were produced by the purified enzyme,with the 100% and 94.3%e.e.value,respec-tively.Therefore,the enzyme could be one of the effective biocatalysts for asymmetric synthesis of chiral alcohols.The amino acid sequences of one peptide from the purified enzyme were analyzed by LC-MASS-MASS,and the car-bonyl reductase showed some identity to the hypothetical protein CaO19.10414 reported.展开更多
基金Sponsored by the National Natural Science Foundation of China(No.20972015)the Natural Science Foundation of Beijing(No.2082016)the Science and Technology Innovation Foundation for the College Students of Beijing(No.B091000814)
文摘A practical chemical synthesis of L-camitine （1） has been accomplished from （R）-3-chloro-1,2-propanediol （（R）-4）, which is a main by-product originated from （R,R）-Salen Co（III） catalyzed hydrolytic kinetic resolution （HKR） of （±）-epichlorohydrin. （R）-4 was utilized as a chiral starting material to prepare the key intermediate cyclic sulfite （（R）-S）. The new synthetic approach demonstrated an efficient utilization of organic by-product for the asymmetric synthesis of bioactive compounds.
基金The authors thank the financial supports from Na-tional Natural Science Foundation of China(Nos.81372796 and 81000278)Shanghai Scientific and Technological Innovation Project(Nos.10431903000 and 124119a2400)Shanghai Bureau of Health(No.20124097).
文摘A novel oridonin derivative substituted with 3-((2,3-dihydroxypropyl)dithio)-propionyl group at 14-O position was synthesized through a two-step procedure:Esterification of oridonin with 3-(2-pyridyldithio)propanoic acid and the subsequent thiol-disulfide exchange reaction with 3-mercapto-1,2-propanediol.The bioreduction-responsive di-sulfide bond in the compound leads to high leaving ability of the 14-O acyl moiety when treated with glutathione as monitored by reverse phase high-performance liquid chromatography.
基金This work was supported by the National Natural Science Foundation of China(Grant No.20376031)the National Key Basic Research and Development Program of China(973 Program)(Grant No.2003CB716008)+1 种基金the Program for New Century Excellent Talents in University,Ministry of Education,China(Grant No.NCET-04-0498)the Program for Changjiang Scholars and Innovative Research Team in University(Grant No.PCSIRT,IRT0532).
文摘A novel NADPH-dependent carbonyl reductase was separated from Candida parapsilosis CCTCC 203011.The enzyme gave a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE),which was purified through ammonium sulfate,Diethylamino Ethanol(DEAE)sepharose Fast flow(FF),phenyl-sepharose FF and blue sepharose FF chromato graphy from cell-free extract.The molecular mass of the enzyme was about 30 kDa.The optimum pH and temperature for reduction were 4.5℃ and 35℃,respectively.The Cu2+had strong restrictive effect on enzyme activity.In addition,the carbonyl reductase was an enzyme with high substrate specificity and stereo-selectivity,and showed high asymmetric reduction activity towards a-hydroxyacetophenone and ethyl 4-chloro acetoacetate.For the asymmetric reduction of a-hydroxyacetophenone and ethyl 4-chloro acetoacetate,(S)-1-phenyl-1,2-ethanediol and(R)-ethyl 4-chloro-3-hydroxybutanoate were produced by the purified enzyme,with the 100% and 94.3%e.e.value,respec-tively.Therefore,the enzyme could be one of the effective biocatalysts for asymmetric synthesis of chiral alcohols.The amino acid sequences of one peptide from the purified enzyme were analyzed by LC-MASS-MASS,and the car-bonyl reductase showed some identity to the hypothetical protein CaO19.10414 reported.
